Influence of Parameters Used to Prepare Sterile Solutions of Poloxamer 188 on Their Physicochemical Properties

The physicochemical properties of emulsions based on poloxamers (triblock copolymers of a hydrophobic polyoxypropylene chain and two hydrophilic polyoxyethylene chains) depend on the composition and preparation method. This study examined the impact of poloxamer P188 concentration, autoclaving mode, heating, and salt presence on the viscosity, particle size distribution, and morphology of particles using viscometric analysis, dynamic light scattering (DLS), and atomic force microscopy (AFM). It was shown that sample preparation affects the particle size and morphology but not the chemical composition of P188. The most similar properties were found for 10% P188 samples sterilized by filtration and autoclaving. The higher autoclave temperature and additional heating of the 10% P188 samples to 70 °C resulted in the formation of larger particles. For 4% P188 samples with 0.6% NaCl, samples heated at 70 °C for 15 h after sterilization filtration and autoclaving were the most similar and homogeneous. The 4% P188 sample with the higher autoclave temperature and subsequent heating had the lowest viscosity. In contrast to 10% P188, for 4% P188 in the presence of salt, the lack of heating resulted in the formation of large particles. The 4% P188 solutions with NaCl were more stable during storage than those with a higher concentration.